Rigid inflatable boats (commonly known as RIBs), are useful in rescue operations, especially in heavy seas, and in a variety of other environments where the good stability, buoyancy, and other properties of these boats are particularly advantageous. In U.S. Pat. No. 4,498,413 a rigid inflated boat has been described which is relatively simple to construct, versatile, relatively inexpensive, and easy to transport. In preferred embodiments illustrated in said applications, the boats have rigid hull portions generally at and below the water level, and flexible hull portions generally at and above the water level. The flexible portion comprises a flexible material, preferably an abrasion resistant fabric, which circumferentially surrounds a plurality of inflatable bladders.
The present invention relates to improved constructions of the rigid inflatable boats illustrated in and described in said co-pending applications, and utilizing the basic concepts of a rigid hull portion and a flexible hull portion. According to the present invention, an eminently practical RIB construction is provided which facilitates the modular construction of a rigid inflatable boat, provides desired stability and other functional characteristics while allowing the boat to be transported or stored in a minimum volume configuration, and utilizes materials that are eminently suited for use as the enclosure for the bladders.
According to one aspect of the present invention, a rigid inflatable boat is provided which includes: a rigid hull portion disposed generally at, and below, the water level of the hull; a flexible hull portion, the flexible hull portion including an enclosure or shroud of flexible material completely circumferentially surrounding a plurality of inflatable bladders, and the flexible hull portion being positioned generally at, and above, the water level of the hull; and connecting means for connecting the flexible hull portion to the rigid hull portion, the connecting means comprising bead means formed on the flexible hull portion, and grooved anchor means formed on the rigid hull portion, and for cooperating with the bead means of said flexible hull portion. The bead means preferably comprises a boltrope or the like, and the grooved anchor means preferably has a C-shape in cross-section.
The enclosure for the bladders, of the flexible hull portion, preferably is of a conforming fabric. The term "conforming fabric" as used in the present specification and claims relates to a fabric that has properties such that it may be formed to the required complex contour without puckering. The majority of conforming fabrics are knit, such as warp knit or circular knit fabrics. However triaxially woven fabric, fabrics woven with elastic therein, velvet, and braided fabric also are conforming fabrics. The enclosure fabric is preferably attached to the boltrope by textile tape and stitching.
It is particularly advantageous to provide memory for the conforming fabric of the enclosure so that it tends to return to its use position, wherein it completely circumferentially encloses inflated bladders. This may be accomplished by impregnating the fabric with a finishing material, such as a resin, and curing it while it is held in its desired use position.
According to another aspect of the present invention, a rigid inflatable boat includes a transom, the transom providing for proper positioning of the flexible hull portion. The sides of the transom may be scalloped to receive the flexible hull portion, and the boltrope may be affixed to the rigid hull portion in the area of the transom. Preferably, the transom is pivotally mounted to the rigid hull portion for pivotal movement about a horizontal axis extending along the dimension of elongation of the transom, so that the transom may be folded down so that the boat will assume a low volume configuration during storage or transport. A brace attached to the rigid hull portion and the transom holds the transom in an upright position during use, and positioning of the flexible hull portion may be facilitated by loosely affixing the enclosure fabric to the brace.
It is the primary object of the present invention to provide a practical, versatile, RIB. This and other objects of the invention will become clear from an inspection of the detailed description of the invention, and from the appended claims.